A quiet milestone in modern astronomy may soon come to pass. As of today, The Extrasolar Planets Encyclopedia lists a current tally of 998 extrasolar planets across 759 planetary systems. And although various tabulations ...

Finding life on exoplanets may be more difficult than people thought, said Feng Tian, a professor at the Center for Earth System Science at Tsinghua University in Beijing, China. The report was presented last week to the ...

An international team, with participation from the University of Bern, has produced the first map of clouds on an exoplanet using the Kepler Space Telescope. Studying the atmospheres of exoplanets is the path towards ultimately ...

(Phys.org) —Scientists at SLAC have found a new method to create coherent beams of twisted light – light that spirals around a central axis as it travels. It has the potential to generate twisted light in shorter pulses, ...

(Phys.org) —On Earth, life leaves telltale signals in the atmosphere. Photosynthesis is ultimately responsible for the high oxygen levels and the thick ozone layer. Microbes emit methane and nitrous oxide into the atmosphere, ...

An international team of astronomers that are members of the Strategic Exploration of Exoplanets and Disks with Subaru Telescope (SEEDS) Project has used Subaru Telescope's High Contrast Instrument for the Subaru Next Generation ...

Extrasolar planet

An extrasolar planet, or exoplanet, is a planet beyond our Solar System, orbiting a star other than our Sun. As of June 2009[update], 353 exoplanets are listed in the Extrasolar Planets Encyclopaedia. The vast majority have been detected through radial velocity observations and other indirect methods rather than actual imaging. Most announced exoplanets are massive gas giant planets thought to resemble Jupiter, but this is a selection effect (bias) due to limitations in detection technology. Projections based on recent detections of much smaller worlds suggest that lightweight, rocky planets will eventually be found to outnumber extrasolar gas giants.

Extrasolar planets became a subject of scientific investigation in the mid-19th century. Many astronomers supposed that such planets existed, but they had no way of knowing how common they were or how similar they might be to the planets of our Solar System. The first confirmed radial velocity detection was made in 1995, revealing a gas giant planet in a four-day orbit around the nearby G-type star 51 Pegasi. The frequency of detections has tended to increase on an annual basis since then. It is estimated that at least 10% of sun-like stars have planets, and the true proportion may be much higher. The discovery of extrasolar planets sharpens the question of whether some might support extraterrestrial life.

Currently Gliese 581 d, the fourth planet of the red dwarf star Gliese 581 (approximately 20 light years from Earth), appears to be the best example yet discovered of a possible terrestrial exoplanet that orbits within the habitable zone surrounding its star. Although initial measurements suggested that Gliese 581 d resided outside the so-called "Goldilocks Zone", additional measurements place it firmly within.